feat(config): add custom json marshaler function

atreugo.go

@@ -41,6 +41,10 @@ func New(cfg Config) *Atreugo {
 		cfg.Logger = defaultLogger
 	}
 
+	if cfg.JSONMarshalFunc == nil {
+		cfg.JSONMarshalFunc = defaultJSONMarshalFunc
+	}
+
 	if cfg.ErrorView == nil {
 		cfg.ErrorView = defaultErrorView
 	}

atreugo_test.go

@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"errors"
 	"fmt"
+	"io"
 	"math/rand"
 	"net"
 	"os"
@@ -32,19 +33,24 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 		network                 string
 		gracefulShutdown        bool
 		gracefulShutdownSignals []os.Signal
+		jsonMarshalFunc         JSONMarshalFunc
 		notFoundView            View
 		methodNotAllowedView    View
 		panicView               PanicView
 	}
 
 	type want struct {
 		gracefulShutdownSignals []os.Signal
+		jsonMarshalFunc         JSONMarshalFunc
 		notFoundView            bool
 		methodNotAllowedView    bool
 		panicView               bool
 		err                     bool
 	}
 
+	jsonMarshalFunc := func(w io.Writer, body interface{}) error {
+		return nil
+	}
 	notFoundView := func(ctx *RequestCtx) error {
 		return nil
 	}
@@ -67,8 +73,7 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 			args: args{},
 			want: want{
 				gracefulShutdownSignals: nil,
-				notFoundView:            false,
-				methodNotAllowedView:    false,
+				jsonMarshalFunc:         defaultJSONMarshalFunc,
 				panicView:               false,
 			},
 		},
@@ -79,6 +84,7 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 			},
 			want: want{
 				gracefulShutdownSignals: defaultGracefulShutdownSignals,
+				jsonMarshalFunc:         defaultJSONMarshalFunc,
 				notFoundView:            false,
 				methodNotAllowedView:    false,
 				panicView:               false,
@@ -90,12 +96,14 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 				network:                 "unix",
 				gracefulShutdown:        true,
 				gracefulShutdownSignals: []os.Signal{syscall.SIGKILL},
+				jsonMarshalFunc:         jsonMarshalFunc,
 				notFoundView:            notFoundView,
 				methodNotAllowedView:    methodNotAllowedView,
 				panicView:               panicView,
 			},
 			want: want{
 				gracefulShutdownSignals: []os.Signal{syscall.SIGKILL},
+				jsonMarshalFunc:         jsonMarshalFunc,
 				notFoundView:            true,
 				methodNotAllowedView:    true,
 				panicView:               true,
@@ -133,6 +141,7 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 				Network:                 tt.args.network,
 				GracefulShutdown:        tt.args.gracefulShutdown,
 				GracefulShutdownSignals: tt.args.gracefulShutdownSignals,
+				JSONMarshalFunc:         tt.args.jsonMarshalFunc,
 				NotFoundView:            tt.args.notFoundView,
 				MethodNotAllowedView:    tt.args.methodNotAllowedView,
 				PanicView:               tt.args.panicView,
@@ -151,25 +160,17 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 				t.Errorf("Logger == %p, want %p", s.cfg.Logger, defaultLogger)
 			}
 
-			if !isEqual(s.cfg.ErrorView, defaultErrorView) {
-				t.Errorf("Error view == %p, want %p", s.cfg.ErrorView, defaultErrorView)
-			}
-
-			if s.router == nil {
-				t.Fatal("Atreugo router instance is nil")
-			}
-
-			if s.router.GlobalOPTIONS != nil {
-				t.Error("GlobalOPTIONS handler is not nil")
-			}
-
 			if !reflect.DeepEqual(tt.want.gracefulShutdownSignals, s.cfg.GracefulShutdownSignals) {
 				t.Errorf(
 					"GracefulShutdownSignals = %v, want %v",
 					s.cfg.GracefulShutdownSignals, tt.want.gracefulShutdownSignals,
 				)
 			}
 
+			if !isEqual(s.cfg.JSONMarshalFunc, tt.want.jsonMarshalFunc) {
+				t.Errorf("JSONMarshalFunc == %p, want %p", s.cfg.JSONMarshalFunc, tt.want.jsonMarshalFunc)
+			}
+
 			if tt.want.notFoundView != (s.router.NotFound != nil) {
 				t.Error("NotFound handler is not setted")
 			}
@@ -178,6 +179,10 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 				t.Error("MethodNotAllowed handler is not setted")
 			}
 
+			if !isEqual(s.cfg.ErrorView, defaultErrorView) {
+				t.Errorf("Error view == %p, want %p", s.cfg.ErrorView, defaultErrorView)
+			}
+
 			if tt.want.panicView != (s.router.PanicHandler != nil) {
 				t.Error("PanicHandler handler is not setted")
 			}
@@ -190,6 +195,14 @@ func Test_New(t *testing.T) { //nolint:funlen,gocognit,gocyclo
 					t.Errorf("Panic handler response == %s, want %s", ctx.Response.Body(), panicErr.Error())
 				}
 			}
+
+			if s.router == nil {
+				t.Fatal("Atreugo router instance is nil")
+			}
+
+			if s.router.GlobalOPTIONS != nil {
+				t.Error("GlobalOPTIONS handler is not nil")
+			}
 		})
 	}
 }

context.go

@@ -17,7 +17,10 @@ var (
 
 	requestCtxPool = sync.Pool{
 		New: func() interface{} {
-			return new(RequestCtx)
+			ctx := new(RequestCtx)
+			ctx.jsonMarshalFunc = defaultJSONMarshalFunc
+
+			return ctx
 		},
 	}
 )

context_test.go

@@ -13,8 +13,12 @@ func Test_AcquireRequestCtx(t *testing.T) {
 	ctx := new(fasthttp.RequestCtx)
 	actx := AcquireRequestCtx(ctx) // nolint:ifshort
 
+	if !isEqual(actx.jsonMarshalFunc, defaultJSONMarshalFunc) {
+		t.Errorf("jsonMarshalFunc = %p, want %p", actx.jsonMarshalFunc, defaultJSONMarshalFunc)
+	}
+
 	if actx.RequestCtx != ctx {
-		t.Errorf("AcquireRequestCtx() = %p, want %p", actx.RequestCtx, ctx)
+		t.Errorf("RequestCtx = %p, want %p", actx.RequestCtx, ctx)
 	}
 }
 
@@ -31,19 +35,19 @@ func Test_ReleaseRequestCtx(t *testing.T) {
 	ReleaseRequestCtx(actx)
 
 	if actx.next {
-		t.Errorf("reset() next is not 'false'")
+		t.Errorf("next is not 'false'")
 	}
 
 	if actx.skipView {
-		t.Errorf("reset() skipView is not 'false'")
+		t.Errorf("skipView is not 'false'")
 	}
 
-	if actx.RequestCtx != nil {
-		t.Errorf("reset() *fasthttp.RequestCtx = %p, want %v", actx.RequestCtx, nil)
+	if actx.jsonMarshalFunc == nil {
+		t.Errorf("jsonMarshalFunc is nil")
 	}
 
 	if actx.RequestCtx != nil {
-		t.Errorf("ReleaseRequestCtx() *fasthttp.RequestCtx = %p, want %v", actx.RequestCtx, nil)
+		t.Errorf("*fasthttp.RequestCtx = %p, want %v", actx.RequestCtx, nil)
 	}
 }
 

response.go

@@ -2,13 +2,18 @@ package atreugo
 
 import (
 	"encoding/json"
+	"io"
 
 	"github.com/valyala/bytebufferpool"
 	"github.com/valyala/fasthttp"
 )
 
+func defaultJSONMarshalFunc(w io.Writer, body interface{}) error {
+	return json.NewEncoder(w).Encode(body) // nolint:wrapcheck
+}
+
 // JSONResponse return response with body in json format.
-func (ctx *RequestCtx) JSONResponse(body interface{}, statusCode ...int) (err error) {
+func (ctx *RequestCtx) JSONResponse(body interface{}, statusCode ...int) error {
 	ctx.Response.Header.SetContentType("application/json")
 
 	if len(statusCode) > 0 {
@@ -17,7 +22,7 @@ func (ctx *RequestCtx) JSONResponse(body interface{}, statusCode ...int) (err er
 
 	w := ctx.Response.BodyWriter()
 
-	return json.NewEncoder(w).Encode(body) // nolint:wrapcheck
+	return ctx.jsonMarshalFunc(w, body) // nolint:wrapcheck
 }
 
 // HTTPResponse return response with body in html format.

response_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"io"
 	"os"
 	"path"
 	"testing"
@@ -23,8 +24,9 @@ func (cj customJSON) MarshalJSON() ([]byte, error) {
 
 func TestJSONResponse(t *testing.T) { //nolint:funlen
 	type args struct {
-		body       interface{}
-		statusCode int
+		body            interface{}
+		statusCode      int
+		jsonMarshalFunc JSONMarshalFunc
 	}
 
 	type want struct {
@@ -42,8 +44,9 @@ func TestJSONResponse(t *testing.T) { //nolint:funlen
 		{
 			name: "ValidBody",
 			args: args{
-				body:       JSON{"test": true},
-				statusCode: 200,
+				body:            JSON{"test": true},
+				statusCode:      200,
+				jsonMarshalFunc: defaultJSONMarshalFunc,
 			},
 			want: want{
 				body:        "{\"test\":true}",
@@ -55,8 +58,9 @@ func TestJSONResponse(t *testing.T) { //nolint:funlen
 		{
 			name: "BodyAsJsonMarshaler",
 			args: args{
-				body:       customJSON{Value: "test"},
-				statusCode: 200,
+				body:            customJSON{Value: "test"},
+				statusCode:      200,
+				jsonMarshalFunc: defaultJSONMarshalFunc,
 			},
 			want: want{
 				body:        "{\"Value\":\"test\"}",
@@ -66,10 +70,29 @@ func TestJSONResponse(t *testing.T) { //nolint:funlen
 			},
 		},
 		{
-			name: "InvalidBody",
+			name: "CustomJSONMarshalFunc",
 			args: args{
 				body:       make(chan int),
 				statusCode: 200,
+				jsonMarshalFunc: func(w io.Writer, value interface{}) error {
+					_, err := w.Write([]byte("my custom response"))
+
+					return err // nolint:wrapcheck
+				},
+			},
+			want: want{
+				body:        "my custom response",
+				statusCode:  200,
+				contentType: "application/json",
+				err:         false,
+			},
+		},
+		{
+			name: "InvalidBody",
+			args: args{
+				body:            make(chan int),
+				statusCode:      200,
+				jsonMarshalFunc: defaultJSONMarshalFunc,
 			},
 			want: want{
 				body:        "",
@@ -88,6 +111,7 @@ func TestJSONResponse(t *testing.T) { //nolint:funlen
 
 			ctx := new(fasthttp.RequestCtx)
 			actx := AcquireRequestCtx(ctx)
+			actx.jsonMarshalFunc = tt.args.jsonMarshalFunc
 
 			err := actx.JSONResponse(tt.args.body, tt.args.statusCode)
 			if tt.want.err && (err == nil) {

types.go

@@ -2,6 +2,7 @@ package atreugo
 
 import (
 	"crypto/tls"
+	"io"
 	"net"
 	"os"
 	"time"
@@ -21,6 +22,8 @@ type preforkServer interface {
 	ListenAndServe(addr string) error
 }
 
+type JSONMarshalFunc func(w io.Writer, value interface{}) error
+
 // Atreugo implements high performance HTTP server
 //
 // It is prohibited copying Atreugo values. Create new values instead.
@@ -111,6 +114,9 @@ type Config struct { // nolint:maligned
 	// in 'Accept-Encoding' header.
 	Compress bool
 
+	// JSONMarshalFunc is used to marshal the response body to writer as JSON.
+	JSONMarshalFunc JSONMarshalFunc
+
 	// Configurable view which is called when no matching route is
 	// found. If it is not set, http.NotFound is used.
 	NotFoundView View
@@ -484,8 +490,9 @@ type StaticFS struct {
 type RequestCtx struct {
 	noCopy nocopy.NoCopy // nolint:structcheck,unused
 
-	next     bool
-	skipView bool
+	next            bool
+	skipView        bool
+	jsonMarshalFunc JSONMarshalFunc
 
 	// Flag to avoid stack overflow when this context has been embedded in the attached context
 	searchingOnAttachedCtx int32